calc_inner_product.m

function K = calc_inner_product(model,model_data,U1,U2)
%function K = calc_inner_product(model,[model_data],U1,U2)
%
% function computing the inner product between all pairs of 
% functions in U1,U2. Result is a matrix K of size size(U1,2) x
% size(U2,2) with the inner products.

% Bernard Haasdonk 20.7.2006
%
% Oliver Zeeb, 21.09.2012
% Original name was fv_inner_product, this function has exactly the same 
% code and does exactly the same! But since it is not only useful for
% FV-functions, the function-name was changed to calc_inner_product

% currently simple diagonal weighting of element values sufficient
if(isempty(model_data))
  model_data = model.gen_model_data(model);
end
W = model.get_inner_product_matrix(model_data);
K = U1' * W * U2;